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最新推荐文章于 2025-08-13 09:35:03 发布

原创最新推荐文章于 2025-08-13 09:35:03 发布 · 238 阅读

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本文介绍了一种基于IIC协议的PCF8591模数/数模转换器的应用实例。通过单片机控制实现对外部模拟信号的连续读取，并将读取到的数据在LCD显示屏上显示。

/*-----------------------------------------------
名称：IIC协议 PCF8591 AD/DA转换
论坛：www.doflye.net
编写：shifang
修改：无
内容：使用4路AD中的1路检测外部模拟量输入
------------------------------------------------*/
#include <reg52.h>
#include "i2c.h"
#include "delay.h"
#include "display.h"

#define AddWr 0x90 //写数据地址
#define AddRd 0x91 //读数据地址

sbit KEY1 = P1^0;
sbit KEY2 = P1^1;

bit flag = 1;
extern bit ack;

extern void InitLcd1602();
extern void LcdShowStr(unsigned char x,unsigned char y,unsigned char *str);
unsigned char ReadADC(unsigned char Chl);
void ValueToString(unsigned char *str,unsigned char val);
bit WriteDAC(unsigned char dat);
/*------------------------------------------------
主程序
------------------------------------------------*/
main()
{
unsigned char num1 = 0,num2 = 0,num3 = 0,num4 = 0;
unsigned char str1[10],str2[10],str3[10],str4[10];

EA = 1;
TMOD = 0x01;
TH0 = 0xFC;
TL0 = 0x67;
ET0 = 1;
TR0 = 1;

Init_Timer0();
InitLcd1602();

while (1) //主循环
{
num1 = ReadADC(0);
ValueToString(str1,num1);
LcdShowStr(0,0,str1);

num2 = ReadADC(1);
ValueToString(str2,num2);
LcdShowStr(8,0,str2);

num3 = ReadADC(2);
ValueToString(str3,num3); dx
LcdShowStr(0,1,str3);

num4 = ReadADC(3);
ValueToString(str4,num4);
LcdShowStr(8,1,str4);
}
}

void InterruptTimer0() interrupt 1
{
static unsigned int cnt = 0;

TH0 = 0xFC;
TL0 = 0x67;
cnt++;
if(cnt >= 1000)
{
cnt = 0;
flag = 1;
}
}

void ValueToString(unsigned char *str,unsigned char val)
{
static unsigned char i = 1;
val = (val*25)/255;
str[0] = 'C';
str[1] = i + '0';
str[2] = ':';
str[3] = val/10+'0';
str[4] = '.';
str[5] = (val/10)%10+'0';
str[6] = val%10+'0';
str[7] = 'v';

i++;
if(i>4)
{
i = 1;
}
}
/*------------------------------------------------
读AD转值程序
输入参数 Chl 表示需要转换的通道，范围从0-3
返回值范围0-255
------------------------------------------------*/
unsigned char ReadADC(unsigned char Chl)
{
unsigned char Val;
Start_I2c(); //启动总线
SendByte(AddWr); //发送器件地址
if(ack==0)return(0);
SendByte(0x40|Chl); //发送器件子地址
if(ack==0)return(0);
Start_I2c();
SendByte(AddWr+1);
if(ack==0)return(0);
Val=RcvByte();
NoAck_I2c(); //发送非应位
Stop_I2c(); //结束总线
return(Val);
}
/*------------------------------------------------
写入DA转换数值
输入参数：dat 表示需要转换的DA数值，范围是0-255
------------------------------------------------*/
/*bit WriteDAC(unsigned char dat)
{
Start_I2c(); //启动总线
SendByte(AddWr); //发送器件地址
if(ack==0)return(0);
SendByte(0x40); //发送器件子地址
if(ack==0)return(0);
SendByte(dat); //发送数据
if(ack==0)return(0);
Stop_I2c();
}*/